Transformer bushing



March 18, E. C. H KER ETAL TRANSFORMER BUSHING Filed May 3o, 1944 IN VEN TORS.

Patented Mar. 18, 1947 TRANSFORMER BUSHING Elmer C. Ilker, Wilmette, and Donald 0. Schwennesen, Chicago, Ill., a'ssignors to Essex Wire Corporation, Chicago, Ill., a corporation of Michigan Application May 30, 1944, Serial No. 538,025

1 Claim. l

The present invention relates to an insulating bushing for electrical connectors or binding posts.

In certain electrical devices, such as transformers, or the like, it is necessary that the devices be hermetically sealed, as when used in war planes which operate in Widely changing temperatures and atmospheric pressures. The conductors for such devices must pass through insulation to the exterior for connection to other parts oi the electrical circuit. There rnust be a good seal between the conducting element and the insulator, and between the .insulator and the housing of the device, as a wall portion thereof, where the conductors pass through.

Among the objects of the invention is to provide a novel electrical insulating bushing, which may be of one piece or of two pieces as herein disclosed, in hermetically sealed relationship, as by way of a gasket composed of suitable material, with the bushing and the wall, an end wall part or portion, of the casing or housing for the transformer; and also such a bushing with a gasket provided in a, well formed in an end por tion of the bushing where the gasket will be pressed in sealed engagement with the conducting terminal extending through the bushing and the wall of the well of the bushing; and also the provision of any of such bushing and sealing means with a backing plate for holding the bushing and the sealing means to the wall portion of the housing. Either or both of such novel means are particularly adapted for use with a non-rotatable type of insulator bushing and terminal. Also, the invention comprehends the provision oi the one piece type of insulator bushing with means for preventing relative rotation of the conducting terminal and the bushing, as by providing the bushing with a transverse slot or the like and the terminal with a flat end head to t into the slot.

The fiat end head part may have a hole for facilitating the making of a solder joint with a wire connected to the fiat end head, so that the latter with the wire and the solder may be drawn into the slot in the insulator bushing to further effect a tight assembly.

A further object of the invention is to provide a. novel structure having the externally round or cylindrical portion of the insulator or bushing separated from the non-circular, such as square in cross section, portion of the insulator bushing, by a preferably integral annular shoulder or collar. An annular gasket is placed over the cylindrical portion land in Contact with the annular flange or collar portion, and then 2 the cylindrical portion is inserted through a hole in the housing to bring the gasket in contact with the wall of the housing around the hole therein. By pressing against the other side of the shoulder or collar a tight connection will be established between the insulator bushing and the housing. The contacting parts of the collar and the housing wall with the gasket are preferably inclined so as to press the gasket componently with a rm sealing contact with the bushing and the housing wall surrounding the opening or hole through which the bushing extends.

Another object of the invention is to provide a. novel structure comprising a, two-piece insulating bushing in which the parts are telescopically connected, as by a, conducting terminal extending through them and headed to hold the parts together and against the opposite sides of the housing wall with a sealing means, as a gasket pressed between the shoulder part of one of the pieces of the bushing and the housing wall where the bushing extends through said wall, the shoulder part being preferably formed with an inclined or sloping face to enhance the pressing of the gasket against the bushing and to the housing wall to form an eiiicient sealing between the bushing and the housing wall. This type of bushing also has a well at its outer end with a sealing gasket in and around the conducting terminal, as in the cases referred to above.

Other objects, advantages, capabilities, features, and the like, are comprehended by the lnvention as will later appear and as are inherently possessed by the invention.

Referring to the drawings:

Figure 1 is a longitudinal sectional view with parts shown in elevation of a device embodying the invention;

Figure 2 is a transverse sectional view taken in a plane represented by line 2--2 in Figure 1 of the drawings;

Figure 3 is a longitudinal sectional view of an insulator bushing and terminal assembly constructed in accordance with the invention;

Figure 4 is a. transverse sectional View taken in a plane represented by line 4-4 in Figure 5 of the drawings;

Figure 5 is a longitudinal sectional view of the bushing and terminal assembly in finished condition;

Figures 6 and '7 are fragmentary sectional views of an end portion of the bushing and terminal in different stages of assembly;

Figures 8 and 9 are similar views of an alternative form;

Referring Amore in detail to the drawings,fthe, embodiments chosen to illustrate the invention are shown with a transformer I in a housing 2 having a closed end wall 3 and an open end 4, all parts being within the side wall or .the side wall extended of the housing 2. Closing the open end 4 of the housing 2 is anY end wall portion `5 having a peripheral flange 5 extending inwardly of the housing 2 and fitting within the open endl 4, with the outer face of the end wall portion 5 substantially flush with or inthe .plane of .the

edge 1 of the open end portion 4 of the housing 2. The edge 1 is preferably flared to afford space for directly applying solder between the end portion 4 .and the flange. 6 to effect a hermetical -seal therebetween. Y

The .end wall portion 5 is provided with a pluralityof round or circuar holes 8 and withv annular ared rims .9 which form inclined seats for the seating of the gaskets or sealing rings I0.' Extending through each hole 8 is an insulator or bushing II having a round or cylindrical shank I2,v an integral annular collar or flange I3, and an `integral non-circular, such as square, head "I4, The collar I3 preferably has an inclined wall Ia for retaining the gasket in `sealing relation to the inclined. rim 9 andthe shank I2 of the insulator bushing I I. Extending longitudinally through the connector II is a conducting terminal I5 which is threaded in part to receive a binding nut I B for clampinga solder4 lug I I and athrust washer: I8, the :latter for pressingpa gasket or sealing ring I9 into a socket or wel1a2 4provided in the outer endportion of the .bushing I I. The inner side wall of this well is preferably inclined.- The other endfof the terminall5 is provided with a flat end head A'2| adapted to fit into a. slot 22 provided, preferablydiagonally, in the head I 4, so as to prevent the rotating of the .element I 5 when the nut I6 is turned, yet to permit longitudinal or axial movement of the element, I5 when desired. The head 2I is preferably provided `with a hole 23 for the passage of an end of a conductor ,or wire 35 (Figs. 3 and 5) running from the transformer I.

For thepurpose of holding-the bushings II in proper relation and in sealed condition to the wall portion 5 the invention comprehends the provision of a retaining plate 24 provided with a plurality of non-circular, such as square, holes. 25, corresponding in position and number with the round or circular holes 8 in the wall portion 5, for the extending through said holes 25 yof the heads I4. By tting the square heads VI4 in the square holes 25 turning of the bushings I I will be prevented when the nut I 6 is turned. The retaining plate `24 is disposed parallel to the wall portionz5; with thecollars or flanges I3 vof the bushings abutting the plate 24 and the gaskets or sealing,V rings AIl) being pressed in sealing condition between .the surfaces i3d of the collarsor flanges I3 and the rims 3 of the Aholes in the.V

plate25. yThesurfaces I3a and the rims .9 may be inclined when desired.- .The retaining plate 24 is held pressed against the collars or fianges I3 bysuitable connecting and, anchoring means, such as struck-outtongues or lugs v25, rigid with the wall portion 5 andhookedover the ends of theplate24, as shown-in Figures 1 and 42, or by suitable connecting elements such as vrivets `or screws with nuts 26a extending through the plate 24 and fixed to the wall 5.

The wall part 5 may be provided with suitable securing elements 21, such as screws, bolts, or the like, for connecting the unit in place.

The transformer I may be connected to and supported by the end wall part 5 by way of brackets 28 located at the sides of the transformer I and connected to the transformer by suitable bolts 29 extending through a part of the transformer body andthrough toe parts 30 of the brackets 28. The outer end of the brackets 28 are preferably secured, as by spot welding, as loci 3l to the flange 6 of thewall part 5. This provides for a rigid support for the transformer l Referring particularly to Figures 3, 4 and 5, the insulator bushing I I is shown as provided with a longitudinal bore through which the conducting element or terminal I5 extends, the outer end portion of the element I5 being threaded to receive a nut I5, andthe inner endof the element l5 having the fiat end head 2i integra] therewith and capable of being drawn from the position shown in Figure 3 into the diagonal slot 22 as shown in Figure 5, whereby a shoulder part 33 of the flat end head 2| vwill seat or abut against the bottom or seat 34 of the slot or recess 22. The inner end of the bore 32 (see Figure 4) is sufficiently large for the entry of the part of the wire 35 soldered to the flat end head 2| as also the solder itself.

At the other end, as the nut IIS is tightened on the threaded part of the terminal I 5, it draws the terminal from the relation shown in Figure 3 to that shown in Figure 5, and incidentally the gasket or sealing ring I9 is forced into the socket or well 2i), the thrust washer I8 pressing against the sealing ring I9. This ring I9 seals the terminal I5 and the insulator bushing I I against the passage of any fluid, whether air, gas or liquid, to andv along the terminal I5.

Referring to Figures 6, '7, 8 and 9, it will be seen that a long gasket Ita may be used (see Figures 6 and '7), which may be of more or less stiff or firm material, and which when it is forced intov the well 20 by the thrust washer le it will fill the well 25 and be firmly pressed with sealing engagement with the terminal i5, the bottom of the well 2li, and the inside wall of the well, as shown in Figure 7; and that a short gasket ISb maybe used (see Figures 8 and 9), which may be of -more or less soft or pliant material, and which .when forced into the well '2li has a pressingwasher or the like Ia of a size to enter into the well V2i! and close it against the escape of the material of the gasket Ish, when the nut I8 is tightened against the solder lug I'I and the washer I3, the latter pressing the washer Ia, as above described, whereby the gasket leb is pressed into the well 2li to be firmly held therein with sealingv engagement with the terminal I5, the bottom of the well 20, and the inside inclined wall of the well, as shown in Figure 9.

When` the bushings II are in place the retainingplate presses against the collars or flanges I3 which in turn press against thegaskets or sealing,

rings I which in turn are pressed and sealed againstthe inclined rims 9 around the holes 8 in the wall part 5. Thus pas-sage of fluid, whether air, gas or liquid, is prevented between the bushing. i I and the wall part 5.

Referring to Figure 10, e, two-piece insulator bushing is shown comprising a body portion 35 having a reduced diameter portion 3l for. extendingthrough -a hole in the wall .part 5, shoulder.

38 being provided at the inner end of the bushing portion 36, as shown, the surface of the shoulder being preferably inclined, as shown, so as to componently press the gasket Ia with a sealing contact with the extension 31. The rim portion 9 of the wall may also be flared, if desired, and as shown in Figure 10, to also componently press the gasket Ilia with its sealing contact With the extension 31, a-s also to press firmly against the shoulder 31 and the ared part 8 for an effective sealing effect. On the opposite side of the wall part 5 and rim 9 and tting over the bushing part 31 is an insulating shoulder 38 pressed against the rim 9, as by a washer 39, which in turn is pressed against the shouder 38 by a spun over end portion 40 of a conducting termina] 4I which may be in the form of a long hollow rivet or the like and extending through the bushing 36-31. A solder lug Ila may be interposed between the washer 39 and the rivet head I0. Also, solder 42 may be applied to x the parts 48, I1a and 39 together and also to close and seal the terminal 4I, as shown in Figure 10. In lieu of spinning over the end of the terminal 4I, a binding screw 43 (see Figure 11), threaded into the end of the extension 31, may be used, and as is clearly shown in Figure 11. Solder 42 may also be applied to the screw 43 and parts I1 and 39 to fix them together.

The other end of the bushing 36 has a well 20 with a gasket I9 held in compressed condition by a washer I8, as in the forms shown in Figures 1, 3 and 5, but in lieu of the nut I6 the washer I 8, as also the solder lug I1, are held in place by a spun over end portion 44 of the terminal 4I. Solder 45 is applied to fix the parts 44, II and I8 together and to close and seal the end oi the terminal 4I.

While we have herein described and upon the drawings shown illustrative embodiments oi the invention, it is to be understood that the invention is not limited thereto but comprehends other constructions, details, arrangements of parts, features, and the like, without departing from the spirit of the invention.

Having thus disclosed the invention, we claim:

In a transformer having a housing provided with an apertured wall part with an inclined rim; an electrical insulating seal comprising a cylindrical body portion of rigid insulating material extending through the aperture of said wall part, said body portion having a centrally disposed longitudinal bore therethrough and having an annular under cut shoulder overlapping the rim portion of the wall part about the aperture therein, said rim inclination and under-cut shoulder cooperating to produce an annular region having a generally wedge-shaped cross section with the widest part of the wedge being nearer the center, a sealing gasket of exible insulating material around said body between said shoulder and rim portion, a conducting terminal extending in said bore through said insulating body, means on said terminal engaging one end of said insulating body for retaining said terminal in said body, a sealing gasket of flexible insulating material around said terminal and engaging the other end of said insulating body for sealing said terminal to said insulating body, and means for pressing 4said insulating body, terminal and apertured wall part together for sealing engagement.

ELMER C. ILKER. DONALD O. SCHWENNESEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,264,816 Treanor Dec. 2, 1941 1,932,456 Gaston Oct. 31, 1933 2,211,659 Johanson Aug. 13, 1940 2,235,429 Henry et al Mar. 18, 1941 2,047,031 Paulson July '7, 1936 2,048,891 Rabezzana July 28, 1936 2,348,254 Hartzell May 9, 1944 2,356,831 De Monte et al Aug. 29, 1944 1,766,593 Bramwell June 24, 1930 

